Related papers: Vortex-unbinding and finite-size effects in Tl2Ba2…
We have simulated the thermodynamics of vortices in a thin film of a type-II superconductor. We make the lowest Landau level approximation, and use quasi-periodic boundary conditions. Our work is consistent with the results of previous…
In high-quality c-axis-oriented MgB2 thin films, we observed high critical current densities (Jc) of 16 MA/cm^2 at 15 K under self fields comparable to those of cuprate high-temperature superconductors. The extrapolated value of Jc at 5 K…
We measured the local magnetic response of a niobium thin film by applying a millitesla-scale AC magnetic field using a micron-scale field coil and detecting the response with a micron-scale pickup loop in a scanning superconducting quantum…
The Landau-Lifshitz (L-L) equation describing the time dependence of the magnetisation vector is numerically integrated fully without any simplifying assumptions in the time domain and the magnetisation time series obtained is Fourier…
Cuprate films offer a unique opportunity to observe vortex tunneling effects, due to their unusually low superfluid density and short coherence length. Here, we measure the magnetoresistance (\textit{MR}) due to vortex motion of a long…
Recent experiments on ultracold Bose gases in two dimensions have provided evidence for the existence of the Berezinskii-Kosterlitz-Thouless (BKT) phase via analysis of the interference between two independent systems. In this work we study…
The longitudinal resistivity (rho_{xx}) and transverse resistivity (rho_{xy}) of MgB2 thin films in the mixed state were studied in detail. We found that the temperature dependencies of rho_{xx} and \rho_{xy} at a fixed magnetic field (H)…
We report on study of the vortex liquid in Pb-doped Bi-2223 single crystal using the in-plane resistivity measurements as a function of temperature and magnetic field up to 6T applied perpendicular to CuO planes. Below Tc at the upper part…
A novel experiment for determination of the charge related to vortices in thin superconducting film is proposed and a number of related experimental set-ups are also theoretically considered. The methods are based on the…
Mechanisms of vortex dynamics and pinning and self-field effects which could account for the thickness dependence of the critical current density J_c of superconducting films are addressed. It is shown that at low magnetic fields B, the 2D…
The Berezinskii-Kosterlitz-Thouless theory for superfluid films is generalized in a straightforward way that (a) corrects for overlapping vortex-antivortex pairs at high pair density and (b) utilizes a dielectric approximation for the…
We characterize the mechanisms of vortex pinning in a superfluid thin film described by the two-dimensional Gross-Pitaevskii equation. We consider a vortex "scattering experiment" whereby a single vortex in a superfluid flow interacts with…
We present studies of the dc magnetization of thin platelike samples of the isotropic type II superconductor PbTl(10%), as a function of the angle between the normal to the sample and the applied magnetic field ${\bf H}$. We determine the…
The ferromagnetic properties of epitaxial La$_{0.5}$Sr$_{0.5}$CoO$_3$ thin films have been studied. The magnetic transition is affected by both strain and finite thickness. We have used a series of films of different thickness and on…
We study the effect of a transport current on the vortex-line lattice in isotropic type-II superconductors in the presence of strong thermal fluctuations by means of 'driven-diffusion' Monte Carlo simulations of a discretized London theory…
Vanadium dioxide with metal-to-insulator transition (MIT) that is triggered by heat, current or light is a promising material for modern active THz/mid-IR metasurfaces and all-optical big data processing systems. Multilayer VO2-based active…
We discuss the crucial role played by finite-size effects and inhomogeneity on the Beresinkii-Kosterlitz-Thouless (BKT) transition in two-dimensional superconductors. In particular, we focus on the temperature dependence of the resistivity,…
We have used Monte Carlo simulations to observe the magnetic behaviour of Ising thin-films with cubic lattice structures as a function of temperature and thickness especially in the critical region. The fourth order Binder cumulant is used…
Vortex dynamics in molybdenum-germanium superconducting films were found to well approximate the unpinned free limit even at low driving forces. This provided an opportunity to empirically establish the intrinsic character of free flux flow…
Measurements of the Hall effect and the resistivity in twinned YBa2Cu3O7-delta thin films in magnetic fields B oriented parallel to the crystallographic c-axis and to the twin boundaries reveal a double sign reversal of the Hall coefficient…